Endocrine Abstracts

The standard technique for the functional imaging of pheochromocytoma and paraganglioma (PPGL) is [123I]-metaiodobenzylguanidine single photon emission computed tomography (MIBG SPECT). However, metastases are more accurately detected by 2-[18F]-Fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET). In a large prospective study of 216 patients evaluated at the NIH for benign or malignant PPGL, we investigated the sensitivity and specificity of FDG PET as compared to MIBG SPECT for localization of (metastases of) PPGL. We also explored whether clues for a genetic diagnosis underlying PPGL can be gained from functional characterization by FDG PET. Cut-off values for FDG PET suvs to distinguish PPGL from normal adrenal glands were established.